Journey with me to the tranquil expanse of the Staines Reservoirs. These reservoirs sit near Heathrow Airport in Surrey. They are a testament to London’s ever-growing need for reliable water. Completed in 1902 the Staines Reservoirs were a joint effort by three London water companies.
The New River Company, the Grand Junction Water Company and the West Middlesex Water Company wanted to construct these reservoirs. These companies aimed to secure a plentiful water supply for London’s expanding population. They recognized the potential of the seasonally waterlogged lands in Staines and Stanwell. Thus the idea for the Staines Reservoirs was born.
To realize their vision they proposed the Staines Reservoir Bill of 1896. It sought full indemnity and compulsory purchase powers. Although facing opposition from landowners and local councils, the bill was eventually enacted. This paved the way for the construction of the reservoirs.
The Staines Reservoirs consist of two large bodies of water. They are the North Reservoir and the South Reservoir. These reservoirs are separated by an embankment dam. This dam stretches over 1030 meters. The embankments feature a puddle clay core. This core prevents seepage. It extends deep into the London Clay beneath. The Staines Reservoirs have a total capacity of over 15 million cubic meters.
Initially, five steam-driven engines pumped water into the Staines Reservoirs from the Staines Reservoirs Aqueduct. Each engine could pump 16 million gallons a day. When the river flow at Bell Weir exceeded 265 million gallons a day the joint company could take any extra. Some water went straight to the filter beds at Hampton. The remaining surplus was pumped into the reservoirs. The North Reservoir’s water level sits three meters higher than the South Reservoir’s level. Water travels from the reservoirs through valve towers into the aqueduct. From there it flows to water treatment plants.
Later, the Metropolitan Water Board took over. Then in 1974, Thames Water Authority assumed control. In 1992, a plan emerged to increase the reservoirs’ capacity. This plan sought to raise the dam walls and remove the dividing embankment.
More recently, in April 2020, a sheet pile cut-off wall was installed. It prevents water leakage.
Beyond their engineering significance the Staines Reservoirs provide a haven for wildlife. The area has been designated a Site of Special Scientific Interest. It hosts various wintering water birds. Tufted ducks, pochard, goosander and goldeneye find refuge here.
The Staines Reservoirs Aqueduct is a vital component of the water supply system. This aqueduct stretches for 13 kilometers. It runs from the River Thames to the Red House distribution reservoir near Kempton Park. Built by the Staines Reservoirs Joint Committee, it ensures a steady flow of water. The maximum flow capacity of the aqueduct is 364 million liters per day.
Water is drawn from the Thames. It then travels underground. It flows through steel siphons and concrete conduits. From the Staines pumping station, water is lifted into the Staines and King George VI reservoirs. In 2014, heavy rains caused the River Colne to back up. The water spilled into the aqueduct. This led to flooding in nearby areas.
Today the Staines Reservoirs stand as a vital part of London’s water infrastructure. They also offer a sanctuary for wildlife. As we conclude our visit take a moment to appreciate the blend of engineering and nature. It is right here at the Staines Reservoirs.